Cladonia squamosula

Structure of condidymic acid (461), isolated from Cladonia squamosula 48), was confirmed by total synthesis 48) (Scheme 57). Ullmann reaction of 2-iodo-di-O-methylolivetol and subsequent cyclodehydration/demethylation of the product with hydrobromic acid gave the symmetrical dibenzofuran intermediate (462). Methylation followed by formylation yielded a mixture of the 4-formyl and 2-formyl dibenzofurans (463) and (464), which were separated chromatographically. 3,7-Dimethoxy-l, 9-dipentyl-2-formyldi-benzofuran (464) was then oxidized and selectively demethylated to yield condidymic acid (461). 

Condidymic Acid, a New Dibenzofuran from the Lichen Cladonia squamosula. 

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See also in sourсe #XX -- [ ]

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